The guardsman was one of a pair guarding a gate.
He marches up and down to relieve the tension of standing still.
As he turned about he noticed that the potential intruder was between him and the gate he was guarding. He showed considerable restraint in using a free hand rather than rifle butt or bayonnet in preventing the person from intruding into the place he was detailed to guard.
I submit, your honour, that the guardsman was merely executing his duty, with remarkable constraint, as ordered. There is, therefore, no case to answer.